Terminal mounting



March 28,1939.- Y L,w HMG 2,152,379

TERMINAL MOUNTING Filed Aug. '7, 1937 1N VENTOR.

ATTORN Y flaw/.s M/ /7//1/6 Patented Mar. 28, 1939 UNITED STATES PATENT OFFICE Standard Transformer Company, Warren,

Ohio, a corporation of Ohio Application August 1,

4 Claims.

This invention relates to improvements in terminal mountings, particularly mountings for bus bars used as terminals oi a transformer. The application of the invention is not necessarily confined to that purpose, however.y

One'of the objects of the invention is the provision of a mounting of this character, of relatively simple low cost construction, so designed as to permit expansion and contraction of the terminal without damage to the insulation employed.

Another` object is the provision of a mounting which shall be oiltight, watertight, and of generally weatherproof construction.

A further object is the provision of a mounting which shall be yieldable to some extent in order to absorb without damage blows or mechanical shocks of various kinds.

Other objects and features of novelty will appear as I proceed with the description of that embodiment ci the invention which, for the purposes of the present application, I have illustrated in the accompanying drawing, in which- Fig. l is a plan View of a fragment of a transformer cover upon which my mounting is employed;

Fig. 2 is an elevational view, partly in vertical section, of the construction of Fig. l; and

Fig. 3 is a cross-sectional view, taken substantially on the line 3-3 of Fig. 2, certain parts being broken away in order to more fully disclose the invention.

In the drawing, a fragment of the cover or other casing member-of an electric transformer is illustrated at It. An opening II is formed in the casing It to accommodate the terminal. In the present instance, the opening is of rectangular shape, but it will be understood that it is made to conform substantially with the cross-sectional shape of the terminal, whatever that may be. As here illustrated, the terminal comprises two bus bars I2 and I 3 that are secured upon opposite sides of an intermediate strap I4 which may be an extremity ci the secondary of the transformer. The strap i4 and the bus bars I2 and I3 are preferably fastened together by rivets I5 and also by weide I5 and Il, in order to effect a good electrical as well as a good mechanical union. The parts I 2, I3, and I4, comprising the terminal, are ordinarily made of copper. Their combined cross-sectional area is less than the area ci the opening II, so that when the terminal is roperly centered in the opening it is everywhere spaced from the sides of the opening, and there 1937, Serial N0. 157,945

is no electrical contact between the terminal and the casing.

At a point spaced outwardly from the casing I0, as illustrated in Fig. 2, I fit a metallic cap I8 onto the terminal. This cap, which is made of some non-ferrous, non-magnetic material, such as gun metal or other bronze, closely and tightly embraces the terminal and is joined thereto by a weld I9. The connection between the terminal and the cap I8 is therefore quite rigid.

Just beneath, or inwardly of, the cap I8 I use a cork or other yieldable washer or gasket 28 provided with a central opening of approximately the same size as the opening II, so as to receive and clear the terminal. Beneath the gasket 29 there is a tubular rigid insulation block 2| which surrounds the terminal and is spaced therefrom likewise with a clearance which may be about the same as that between the terminal and the casing in the opening II. This space is illustrated in Fig. 2 at 22. Below the block 2I, which is prete erably of porcelain, there is another gasket 23, which may be of the same size and thickness as the gasket 28, and is provided with a central opening of the same shape and size as that of gasket 20.

The casing IIJ has formed therethrough four holes 24. In alignment with these holes there are four holes 25 through the block 2`I, the lower ends of the latter holes being enlarged to the same diameter as the holes 24. Gasket 23 is provided with holes 26 of the same size as holes 24, and gasket 20 is provided with holes 21 of the same size as the upper portions of holes 25. A ber or other insulating tube 28 lits loosely within the holes 24 and 26 and the large part of the holes 25, and a shorter tube 29 of similar material surrounds tube 28 below or within the casing I0. The cap I8 is secured to the casing I0 by means of bolts or machine screws 38 that extend upwardly from within the casing through washers 3l, through tube 28, through the smaller diameter part of hole 25, through hole 2'I in gasket 2), into threaded relation with cap I 8. It will be understood that there are four of these bolts or screws as illustrated herein, but that a greater or lesser number may be employed if desired. These fastenlngs are made of non-ferrous, nonmagnetic material, such as bronze. It will be noted that they do not extend through cap I8, and hence no moisture is admitted there. When these fastenings are drawn up tightly, the cap is rmly attached to the casing, but because of the yieldability of the gaskets 20 and 23, the various parts of the mounting, particularly the porcelain block 2|, are cushioned against shock. The gaskets 20 and 23 serve to prevent any admission of moisture from the outside of the mounting and any loss of transformer oil from the interior of the transformer.

When the cap I8 is bolted down to the casing I0 in the manner described, there is no possibility of the terminal contacting either the rigid nsulating material of block 2 I, or the walls of opening II in the casing, because the weld I9 and the fit of the terminal in the cap hold the terminal in relatively xed position. On this account contraction and expansion of the terminal sets up no strains or stresses in the insulation. Any external stresses which may be communicated to the block 2|, as by blows or shocks upon the cap I8 or bus bars I2, I3, will be in compression, and since porcelain has a high compressive strength, it is well adapted to take such shocks. However, even these shocks will be cushioned by the gaskets 20 and 23. Since the hole 25 in block 2| is larger than the shank of screw 30, and since the tube 23 loosely engages the shank of the screw and is in turn loosely mounted in hole 24, expansion and contraction either of the cap I8 or of the casing II) will not transmit to the block 2| any force which might tend to cause disintegration of the latter.

Variations from the described structure may be employed. Accordingly, I desire it to be understood that the scope of the invention is to be regarded as being defined exclusively by the appended claims rather than by the foregoing description or the accompanying illustration.

Having thus described my invention, I claim:

1. In a terminal mounting for a transformer casing, a terminal, a cap adapted to be arranged outside the`casing through which the terminal extends and to which it is tightly fitted, a tubular insulation block surrounding but spaced from the terminal and disposed inwardly of the cap and outwardly of the casing, an insulation gasket surrounding the terminal adjacent the said block, fastening means arranged to extend through said casing, through said gasket and block and into a downwardly opening socket in said cap for holding the parts together and securing the mounting to the casing, and insulation arranged to prevent the grounding of said cap through said fastening means.

2. In a terminal mounting, a terminal, a metal cap through which the terminal extends and to which it is secured, said cap being adapted to stand above a casing with which the mounting is employed, a tubular insulation block surrounding but not touching the terminal and disposed beneath the cap and above the casing, a plurality of screws for attachment to the casing adapted to extend loosely therethrough and through openings in the insulation block and anchored in downwardly opening sockets in the said cap, and insulation between said screws and the casing.

3. In a terminal mounting, a terminal, a metal cap through which the terminal extends and to which it is secured, two spaced yieldable insulation gaskets surrounding the terminal inwardly of said cap, a rigid block of insulation material surrounding the terminal between said gaskets but spaced away from the terminal, fastening means for attaching the cap, block and gaskets to a supporting member externally thereof comprising an elongated element extending through the supporting member, through both gaskets and said block and threaded into a downwardly opening socket in said cap, and insulation means arranged to prevent the grounding of said cap through said fastening means.

4. In a terminal mounting for a. transformer casing having an opening therethrough, a terminal of smaller cross-section than said opening adapted to extend through the opening into the casing without touching the latter, a tubular insulation block surrounding the terminal outwardly of the casing spaced away from the terminal, a metal cap fitted tightly to the terminal outwardly of said block, fastenings extending through the casing and block and into a downwardly opening socket in said cap, said block serving as a spacer between said cap and said casing, and insulation means arranged to prevent the grounding of said cap through said fastenings.

LEALDAS W. HAIG. 

